In a known device comprising a LED or an OLED, an electronic switching driver is applied to provide a suitable load current to the (O)LED. Such a device may be a LCD display having a (O)LED backlight, an automotive light assembly, e.g. a rear combination light (RCL) or any other lighting device. Such an electronic switching driver is in general preferably a low-cost circuit.
A suitable low-cost switching driver circuit may be a known self-oscillating driver circuit. Such a switching driver circuit comprises a self-oscillating switch circuit. A known self-oscillating switch circuit is designed to operate in a critical mode, thereby allowing to provide a single power level to a load such as a LED. However, in a number of applications, e.g. in an automotive rear combination light (RCL), at least two power levels are desired. Referring to the exemplary rear combination light, a tail lighting mode and a break lighting mode are desired.
Further referring to the rear combination light, pulse width modulation (PWM) for dimming the LED in a tail lighting mode may result in undesirable artifacts. These artifacts may be such that drivers do not observe the lighting correctly, which may result in accidents.